1. Field of the Invention
This invention relates to a reflection-type bandpass filter for use in ultra-wideband (UWB) wireless data communication.
2. Description of the Related Art
This invention relates to a reflection-type bandpass filter for use in ultra-wideband (hereafter “UWB”) wireless data communication. By using this UWB reflection-type bandpass filter, U.S. Federal Communications Commission requirements for spectrum masks can be satisfied.
As technology of the prior art related to this invention, for example, the technology disclosed in the following references 1 through 12 is known.
Reference 1: Specification of U.S. Pat. No. 2,411,555
Reference 2: Japanese Unexamined Patent Application No. 56-64501
Reference 3: Japanese Unexamined Patent Application No. 9-172318
Reference 4: Japanese Unexamined Patent Application No. 9-232820
Reference 5: Japanese Unexamined Patent Application No. 10-65402
Reference 6: Japanese Unexamined Patent Application No. 10-242746
Reference 7: Japanese Unexamined Patent Application No. 2000-4108
Reference 8: Japanese Unexamined Patent Application No. 2000-101301
Reference 9: Japanese Unexamined Patent Application No. 2002-43810
Reference 10: A. V. Oppenheim and R. W. Schafer, “Discrete-time signal processing,” pp. 465-478, Prentice Hall, 1998.
Reference 11: G-B. Xiao, K. Yashiro, N. Guan, and S. Ohokawa, “An effective method for designing nonuniformly coupled transmission-line filters,” IEEE Trans. Microwave Theory Tech., vol. 49, pp. 1027-1031, June 2001.
Reference 12: Y. Konishi, “Microwave integrated circuits”, pp. 19-21, Marcel Dekker, 1991
However, the bandpass filters proposed in the prior art may not satisfy the FCC specifications, due to manufacturing tolerances and other reasons.
Among bandpass filters from the prior art, a bandpass filter with a configuration wherein one microstrip line is provided on a substrate requires a ground conductor below a dielectric. Therefore, for example, it is difficult for this bandpass filter to configure a circuit together with an antenna having a flat dipole antenna and to be used.
Furthermore, among bandpass filters from the prior art, bandpass filters which use coplanar strips do not use wide ground strips, and so are not suitable for coupling with transmission lines such as slot lines.
This invention has as an object the provision of a high-performance UWB reflection-type bandpass filter which configures the circuit easily and is easy to use, and which satisfies FCC specifications.
Furthermore, this invention has as an object the provision of a high-performance UWB reflection-type bandpass filter which has excellent coupling characteristics with transmission lines such as slot lines, and which satisfies FCC specifications.